Submission #402657

#	Time	Username	Problem	Language	Result	Execution time	Memory
402657		Ruxandra985	Bigger segments (IZhO19_segments)	C++14	100 / 100	126 ms	14948 KiB

segments

#include <bits/stdc++.h>
#define DIMN 500010
using namespace std;
pair <int, int> dp[DIMN];
int v[DIMN];
long long sp[DIMN];
int main()
{
    FILE *fin = stdin;
    FILE *fout = stdout;
    int n , i , st , dr , mid;
    fscanf (fin,"%d",&n);
    for (i = 1 ; i <= n ; i++){
        fscanf (fin,"%d",&v[i]);
        sp[i] = v[i] + sp[i - 1];
        dp[i] = make_pair(1 ,  1);/// o secventa, incepe la 1 si se termina la i
    }

    for (i = 1 ; i <= n ; i++){

        if (i > 1){

            /// 1. iei o sg secventa de la 1 la i, initializat
            /// 2. prelungesti cu 1 secventa de la i - 1

            if (dp[i].first < dp[i - 1].first || (dp[i].first == dp[i - 1].first && dp[i].second < dp[i - 1].second)){
                dp[i].first = dp[i - 1].first;
                dp[i].second = dp[i - 1].second;
            }

        }

        /// acuma ma duc in unele mai mari

        st = i + 1;
        dr = n;
        while (st <= dr){
            mid = (st + dr)/2;

            if (sp[mid] - sp[i] >= sp[i] - sp[dp[i].second - 1]) /// e ok
                dr = mid - 1;
            else st = mid + 1;

        }

        /// solutia in st

        if (dp[st].first < dp[i].first + 1 || (dp[st].first == dp[i].first + 1 && i + 1 > dp[st].second)){
            dp[st].first = dp[i].first + 1;
            dp[st].second = i + 1;
        }


    }

    fprintf (fout,"%d",dp[n].first);


    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int main()':
segments.cpp:12:12: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     fscanf (fin,"%d",&n);
      |     ~~~~~~~^~~~~~~~~~~~~
segments.cpp:14:16: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |         fscanf (fin,"%d",&v[i]);
      |         ~~~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27